diff --git a/doc/manual.rst b/doc/manual.rst
index bb2650799b..19a5355a26 100644
--- a/doc/manual.rst
+++ b/doc/manual.rst
@@ -433,7 +433,7 @@ Numerical constants are of a single type and have the form::
   UINT64_LIT = INT_LIT ['\''] ('u' | 'U') '64'
 
   exponent = ('e' | 'E' ) ['+' | '-'] digit ( ['_'] digit )*
-  FLOAT_LIT = digit (['_'] digit)* (('.' (['_'] digit)* [exponent]) |exponent)
+  FLOAT_LIT = digit (['_'] digit)* (('.' digit (['_'] digit)* [exponent]) |exponent)
   FLOAT32_SUFFIX = ('f' | 'F') ['32']
   FLOAT32_LIT = HEX_LIT '\'' FLOAT32_SUFFIX
               | (FLOAT_LIT | DEC_LIT | OCT_LIT | BIN_LIT) ['\''] FLOAT32_SUFFIX